Method for Real Vehicle Simulation Test of Commercial Vehicle Brake with Wheel Side Electric Drive Assembly Using a Test Bench

Abstract

The present invention discloses a method for conducting a real vehicle simulation test of a commercial vehicle brake pulley side electric drive assembly using a test bench. A sample is installed on the mounting bench to simulate the real vehicle state. At the same time, the output shaft of the sample is connected to the first transmission shaft. A battery simulator, a liquid cooling circulation system, a brake pressure simulator, and a control system are connected. The real vehicle state is achieved by adjusting the number of flywheel discs on the flywheel shaft that can rotate with it, and simulating the moment of inertia through the control system and the bench motor, so that the main shaft has the same load as when the sample is installed on the real vehicle. Then, the acceleration performance test of the sample is carried out, or a steep slope starting simulation test, or a braking performance test, or a road durability test, or a regenerative braking simulation test. For components that integrate braking and driving, braking and driving tests can be carried out on the same test bench. Multiple tests can be completed with just one installation, which reduces the complexity of the test. System-level tests combining braking and driving can also be carried out.

Description

[0001] (Parent case: Chinese Patent 2022104249658) Technical Field

[0002] The present invention belongs to the technical field of safety and reliability testing and verification of automobile brake systems and drive systems, and in particular relates to a real vehicle simulation test method for a commercial vehicle brake pulley side electric drive assembly using a test bench. Background Art

[0003] With the rapid development of intelligent and connected vehicles, brake-by-wire and drive-by-wire technologies have become a research hotspot for automotive and cross-industry companies. First, components on vehicles that use pneumatic / hydraulic pressure as a medium are gradually being replaced by components that use electricity as a transmission medium. Second, vehicle drive modes are evolving from fuel engines or drive motors located in the engine compartment to central electric drive axles, wheel-side electric drive axles, and wheel-side electric drive assemblies. Third, vehicle motion control methods are evolving from single-braking system control and single-drive system control to integrated braking and drive coordinated control, such as hill-start assist and brake energy regeneration. Typical brake-by-wire and drive-by-wire components include EMB (Electromechanical Braking System), electric mechanical brakes, wheel-side electric drive assemblies, and control systems.

[0004] In the prior art, the test bench and test method for this component are to conduct braking or driving tests separately on the corresponding test bench. It needs to be installed multiple times during the test, which makes the test cumbersome and makes it impossible to carry out system-level tests combining braking and driving. Summary of the Invention

[0005] The present invention proposes a real vehicle simulation test method for a commercial vehicle brake pulley side electric drive assembly using a test bench. For components with integrated braking and driving, braking and driving tests can be performed on the same test bench.

[0006] To this end, the technical solution adopted by the present invention is: a real vehicle simulation test method for a commercial vehicle brake pulley side electric drive assembly using a test bench, the test bench includes an environmental simulation box for simulating temperature, humidity and wind speed in an actual environment, the environmental simulation box cover is arranged at the left end of the test bench, the test bench is provided with a mounting table for mounting a sample in the environmental simulation box, the test bench is provided with an intermediate support seat, and the intermediate support seat is located outside the environmental simulation box, a first transmission shaft is provided on the left side of the intermediate support seat, the first transmission shaft extends into the environmental model box and is connected to the output shaft of the sample, a second transmission shaft is provided on the right side of the intermediate support seat, a torque sensor is provided between the first transmission shaft and the second transmission shaft, a flywheel shaft is provided on the right side of the second transmission shaft, the flywheel shaft is mounted on the flywheel frame of the test bench, at least one flywheel disc is sleeved on the flywheel shaft, a third transmission shaft is provided on the right side of the flywheel shaft, the right end of the third transmission shaft is connected to the bench motor fixed to the right end of the test bench, and the combination of the first transmission shaft, the second transmission shaft, the flywheel shaft and the third transmission shaft constitute a main shaft;

[0007] It also includes a control system, a brake pressure simulator connected to the brake of the sample, a battery simulator electrically connected to the regenerative braking system and controller of the sample, a liquid cooling circulation system for simulating the temperature of the cooling medium in the sample, and a slope resistance loading device for simulating steep slope starting. The brake pressure simulator simulates the pressure input to the brake of the sample when the brake pedal is depressed by the input brake pressure. The battery simulator simulates the battery power supply of the car by the voltage input to the controller of the sample. The battery simulator is also used to simulate the sample's recovery of braking energy under regenerative braking conditions. The brake pressure simulator, torque sensor, and battery simulator are all electrically connected to the control system. The liquid cooling circulation system is connected to the cooling system of the sample through a pipeline. The slope resistance loading device includes a slope loading motor. The output end of the slope loading motor is provided with a speed reducing torque multiplier and a torque limiting component. A transmission component is provided between the torque limiting component and the flywheel shaft.

[0008] The sample is mounted on the mounting table in a simulated real vehicle state, and the output shaft of the sample is connected to the first transmission shaft, and the battery simulator, liquid cooling circulation system, brake pressure simulator, and control system are connected. The real vehicle state is achieved by adjusting the number of flywheel discs on the flywheel shaft that can rotate with it, and simulating the moment of inertia through the control system and the bench motor, so that the main shaft has the same load as when the sample is installed on the real vehicle and starts; then the acceleration performance test of the sample, or the steep slope starting simulation test, or the braking performance test, or the road durability test, or the regenerative braking simulation test is carried out. The formulas that need to be used during the test include the calculation formula for the moment of inertia of the main shaft corresponding to the simulation of the real vehicle state, the conversion formula between the main shaft speed and the vehicle speed, and the calculation formula for the torque to be applied to the main shaft when simulating slope control;

[0009] The calculation formula for the rotational inertia of the corresponding spindle when simulating the actual vehicle state is as follows:

[0010] I=G m r 2

[0011] Where: I is the calculated value of the moment of inertia, unit is kg·m 2 ; G m The maximum design total mass of the vehicle is distributed to the mass of the wheel corresponding to the brake in the sample according to the design value of the braking force distribution ratio, the unit is kg; r is the rolling radius of the wheel, the unit is m;

[0012] The conversion formula between spindle speed and vehicle speed is as follows:

[0013] n=2.65v / r

[0014] Where: n is the spindle speed, the unit is r / min; v is the simulated actual vehicle speed, the unit is km / h;

[0015] The formula for calculating the torque to be applied to the main shaft when simulating ramp control is as follows:

[0016] T s =G m ×sin(arctan(i / 100))×r

[0017] Where: T s The torque required to simulate ramp control is in r / min; i is the ramp gradient in %.

[0018] Further preferably, the accelerated performance test comprises the following steps:

[0019] S1: Let the test bench motor be in a free-rotating state, or keep the rotational inertia simulation running;

[0020] S2: Keep the brake in the sample in the released state;

[0021] S3: Simulate the maximum opening of the electronic throttle. Control the controller output of the sample through the control system to accelerate the drive motor of the sample. Record the time from the given control input signal to the start of the drive motor of the sample to the rotation of the main shaft to reach the simulated real vehicle speed of 100 km / h. Draw an acceleration performance curve with time as the horizontal axis and vehicle speed as the vertical axis.

[0022] Further preferably, the steep slope starting simulation test includes the following steps:

[0023] S1: Make the gantry motor in a free-rotating state;

[0024] S2: The control system controls the controller of the prototype to simulate pressing the brake pedal or parking conditions, so that the spindle is locked. When the prototype controller is in the parking condition, the control system controls the prototype controller to simulate pressing the brake pedal first and then releasing the parking condition.

[0025] S3: Calculate the corresponding torque value according to the formula based on the ramp to be simulated, and apply it to the main shaft in the reverse direction through the ramp resistance loading device;

[0026] S4: Use the control system to simulate releasing the brake pedal. After pausing for a specified time interval, quickly press the accelerator pedal to the set opening to start the drive motor of the sample until the spindle speed is greater than 10r / min. Then release the torque applied by the ramp resistance loading device. Record the relationship curve of variables such as the brake pedal release signal, the accelerator pedal pressing control signal, the spindle speed and the torque applied on the ramp resistance loading device over time, so as to obtain the steep slope starting simulation test curve.

[0027] It is further preferred that when conducting a braking performance test, the sample is installed to simulate the actual vehicle state, the drive motor and controller of the sample are not involved in the work or are in a non-enabled state, or the brake part of the sample is tested separately, and the test steps are carried out in accordance with the standard requirements.

[0028] Further preferably, the road durability test includes the following steps:

[0029] S1: The test cycle conditions are selected according to the standard based on the type of vehicle the sample is equipped with, or a multi-level road spectrum is formulated according to the requirements of the user;

[0030] S2: Under the requirements of the moment of inertia corresponding to the simulated actual vehicle state, the control system controls the frame motor to simulate driving resistance, and controls the sample motor by changing the opening of the electronic throttle to simulate the acceleration, holding or coasting of the vehicle. The brake of the sample is controlled by changing the opening of the brake pedal to simulate the deceleration of the vehicle. When regenerative braking control is involved in the deceleration process, the control strategy of the actual vehicle controller is used to make the vehicle speed corresponding to the spindle speed correspond to the second-by-second data of the test cycle condition, and continue to run until the end of the specified cycle;

[0031] S3: After the cycle is completed, inspect the abnormal conditions of each component of the sample as required, as well as the performance and function degradation after endurance.

[0032] Further preferably, the regenerative braking simulation test includes the following steps:

[0033] S1: Turn on the braking energy recovery function;

[0034] S2: Select the initial braking speed as specified, and conduct tests at no less than five points within the specified braking pressure range, with equal spacing between test pads. Conduct a braking test for each braking pressure corresponding to each initial braking speed, and record the measured battery simulator voltage and feedback current during each braking test, as well as the initial braking speed, initial braking temperature, maximum braking temperature, braking time, braking pressure, and output braking torque of each braking test. Calculate the recovered braking energy using the recovered braking energy calculation formula.

[0035]

[0036] Where: E1 is the energy recovered by the regenerative braking system during a single braking process and ultimately fed back to the battery simulator, in Wh; I is the current fed back to the battery simulator during a single braking process, in A; U is the voltage across the battery simulator during a single braking process, in V; t1 is the start time of the effective braking time period, in seconds; t2 is the end time of the effective braking time period, in seconds.

[0037] It is further preferred that each flywheel disc can be fixed to the flywheel frame by a corresponding detachable fixing structure, the detachable fixing structure includes two fixing brackets located on the outside of the corresponding flywheel disc and fixed on the flywheel frame, and the flywheel shaft is provided with a protrusion that can be clamped with the corresponding flywheel disc; when the flywheel disc rotates together with the flywheel shaft, the flywheel disc is sleeved on the protrusion and connected to the flywheel shaft by bolts, and the fixing bracket is not connected to the flywheel disc; when the flywheel disc does not rotate together with the flywheel shaft, the flywheel disc is sleeved on the flywheel shaft except the protrusion and the bolt connection between the flywheel shaft and the flywheel shaft is disconnected, and the fixing bracket is connected to the flywheel disc by bolts.

[0038] The beneficial effects of the present invention are as follows: This test method is applicable to product development, research, quality inspection and quality improvement of commercial vehicle brake assemblies (including pneumatic disc brake assemblies, drum brake assemblies, electric mechanical brakes), wheel-side electric drive assemblies and controllers; for components integrating braking and driving, braking and driving tests can be carried out on the same test bench, and multiple tests can be completed by only one installation, reducing the complexity of the test, and system-level tests combining braking and driving can also be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the gantry in the present invention.

[0040] Figure 2 It is a schematic diagram of the acceleration performance curve in the present invention.

[0041] Figure 3 Schematic diagram of the steep slope starting simulation test curve in the present invention.

[0042] Figure 4 This is the Chinese city bus driving condition curve diagram used as the basis for the road durability test of the present invention.

[0043] Figure 5 This is the driving condition curve of ordinary Chinese passenger cars used as the basis for the road durability test of the present invention.

[0044] Figure 6 This is a driving condition curve diagram of Chinese trucks (GVW≤5500kg) based on which the road durability test of the present invention is conducted.

[0045] Figure 7 This is a driving condition curve diagram of Chinese trucks (GVW>5500kg) based on which the present invention conducts road durability tests.

[0046] Figure 8 This is the Chinese dump truck driving condition curve diagram used as the basis for the road durability test of the present invention.

[0047] Figure 9 This is the Chinese semi-trailer tractor train driving condition curve diagram used as the basis for the road durability test of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described below by way of examples and in conjunction with the accompanying drawings:

[0049] like Figure 1As shown, a method for conducting a real-vehicle simulation test of a commercial vehicle brake pulley side electric drive assembly using a test bench is shown. The test bench mainly consists of a test bench 6, an environmental simulation box 3, a mounting table 4, a first transmission shaft 7, an intermediate support seat 8, a torque sensor 9, a second transmission shaft 11, a flywheel frame 12, a flywheel shaft, a flywheel disc 13, a third transmission shaft 15, and a test bench motor 16. The environmental simulation box 3 is used to simulate the temperature, humidity, and wind speed in an actual environment. The environmental simulation box 3 is covered at the left end of the test bench 6. The test bench 6 is provided with a mounting table 4 for mounting a sample 5 within the environmental simulation box 3. The test bench 6 is provided with an intermediate support seat 8, and the intermediate support seat 8 is located outside the environmental simulation box 3. The first transmission shaft 7 is provided on the left side of the intermediate support seat 8 and extends into the environmental model box 3 to connect with the output shaft of the sample 5. The second transmission shaft 11 is provided on the right side of the intermediate support seat 8, and the torque sensor 9 is provided between the first transmission shaft 7 and the second transmission shaft 11. A flywheel shaft is provided on the right side of the second transmission shaft 11. The flywheel shaft is mounted on the flywheel frame 12 of the test bench. At least one flywheel disc 13 is sleeved on the flywheel shaft. A third transmission shaft 15 is provided on the right side of the flywheel shaft, and the right end of the third transmission shaft 15 is connected to the bench motor 17 fixed to the right end of the test bench 6. To facilitate the support of the second transmission shaft 11 and the third transmission shaft 15, the combination of the first transmission shaft 7, the second transmission shaft 11, the flywheel shaft and the third transmission shaft 15 becomes the main shaft. To ensure the protection of the entire main shaft, a transmission shaft protective cover fixed to the test bench 6 is sleeved on the outside of the second transmission shaft 11 and the third transmission shaft 15. When the entire test bench 6 has a protective cover, the transmission shaft anti-slip cover can be omitted. The mounting table 4 can be replaced according to the actual test.

[0050] Also provided are a control system 17, a brake pressure simulator 10 connected to the brakes of sample 5, and a battery simulator 1 electrically connected to the regenerative braking system and controller of sample 5. The brake pressure simulator 10 simulates the pressure input to the brakes of the sample when the brake pedal is depressed by inputting brake pressure. The battery simulator 1 simulates the vehicle's battery power supply by inputting voltage to the sample's controller. The battery simulator 1 can also be used to simulate the sample's recovery of braking energy under regenerative braking conditions. The brake pressure simulator 10, torque sensor 9, and battery simulator 1 are all electrically connected to the control system 17. The specific structure of the battery simulator 1 is a programmable power supply with a feedback function. An ammeter is then provided on the output circuit of the battery, and voltmeters are provided at both ends of the battery. The opening of the electronic throttle can be simulated by changing the magnitude of its output voltage.

[0051] The brake pressure simulator 10 can be selected as a corresponding brake voltage simulator, brake hydraulic simulator or brake air pressure simulator according to the specific situation. For commercial vehicles with pneumatic brake systems, when the brake pedal is pressed, the brake valve will be controlled to output a certain pressure of brake air pressure to the brake. The brake air pressure simulator is an air pressure regulating device that can adjust the output air pressure and is connected to the sample brake through an air pressure pipeline. For vehicles with hydraulic systems, when the pedal is pressed, a certain pressure of hydraulic pressure will be output to the brake. The brake hydraulic simulator is a hydraulic regulating device that can adjust the output hydraulic pressure and is connected to the sample brake through a hydraulic pipeline. For EMB electric mechanical brakes, when the pedal is pressed, a corresponding voltage will be output to the brake according to the degree of pedal opening. The brake voltage simulator is a power supply that can change the output voltage and is electrically connected to the sample controller through a wire.

[0052] A liquid cooling circulation system 2 is also provided for simulating the temperature of the cooling medium in the sample. The liquid cooling circulation system 2 is connected to the cooling system of the sample 5 via a pipeline. The liquid cooling circulation system mainly consists of a filter, a water pump, a condenser, and a heating device.

[0053] A slope resistance loading device 14 for simulating steep slope starting is also provided. The slope resistance loading device 14 includes a slope loading motor. The output end of the slope loading motor is provided with a speed reducing torque increaser and a torque limiting component. A transmission component is provided between the torque limiting component and the flywheel shaft. The torque limiting component can adopt a clutch, and the transmission component can be a belt drive, a gear drive, etc. The speed reducing torque increaser can be a transmission component with a transmission ratio less than 1 that is provided together with the transmission component.

[0054] Each flywheel disc 13 can be fixed to the flywheel frame 12 by a corresponding detachable fixing structure. The detachable fixing structure includes two fixing brackets located outside the corresponding flywheel disc 13 and fixed to the flywheel frame 12. The flywheel shaft is provided with a protrusion that can be clamped with the corresponding flywheel disc. When the flywheel disc 13 rotates together with the flywheel shaft, the flywheel disc 13 is mounted on the protrusion and connected to the flywheel shaft by bolts (or pins), and the fixing brackets are not connected to the flywheel disc 13. When the flywheel disc 13 does not rotate together with the flywheel shaft, the flywheel disc 13 is mounted on the flywheel shaft except for the protrusion and is disconnected from the flywheel shaft. The fixing brackets are connected to the flywheel disc 13 by bolts. The detachable fixing structure can also be set as a hoisting structure, which can hoist the flywheel disc that does not rotate with the flywheel shaft.

[0055] Prototype 5 was mounted on mounting platform 4 to simulate a real vehicle. The output shaft of Prototype 5 was connected to the first drive shaft 7. The battery simulator 1, liquid cooling system 2, brake pressure simulator 10, and control system 17 were also connected. The real vehicle state was achieved by adjusting the number of flywheel discs on the flywheel shaft that rotated with it, and simulating the moment of inertia through control system 17 and test bench motor 16. This ensured that the spindle was subjected to the same load as when the prototype was installed on a real vehicle. The ambient temperature and humidity on the prototype's exterior, wind speed, battery voltage, motor and controller voltage, and the temperature of the cooling medium flowing through the prototype were controlled as required. This test bench did not account for vertical vehicle loads on the prototype; if necessary, loading could be achieved by adding a hydraulic servo system. Prototype 5 was designed to integrate a commercial vehicle brake assembly (which could be a pneumatic disc brake assembly, a drum brake assembly, or an electromechanical brake (EMB)), a wheel-side electric drive assembly, and a controller. The installation form of the sample can be selected according to different test items, such as a conventional structure with a wheel hub (including a tire), an independent wheel rim structure, a structure with air suspension or a whole bridge (axle) structure.

[0056] The test bench with the sample installed can conduct acceleration performance tests, braking performance tests, thermal crack tests, high-load tests, brake impact tests, temperature rise tests, steep start simulation tests, road simulation endurance tests, and regenerative braking simulation tests, among other bench tests for product development, research, quality inspection, and quality improvement. If the sample is not equipped with a hill-start assist function, the steep start simulation test is not performed. In these tests, the flywheel and bench motor are controlled to accurately simulate vehicle load; the spindle speed is controlled by the bench motor or the wheel-side electric drive assembly motor (i.e., the drive motor of the sample) to simulate vehicle speed; the road slope load or driving resistance is simulated by the slope resistance loading device and bench motor; the brake pedal input is simulated by a brake pressure simulator; a battery simulator is used to accurately control the input voltage of the wheel-side electric drive assembly motor and controller and recover brake energy under regenerative braking conditions; a liquid cooling circulation system is used to control the internal medium temperature of the wheel-side electric drive assembly and controller; and an environmental test chamber is used to simulate various extreme test environments such as high temperature, low temperature, and humidity.

[0057] The formulas required for the test include the calculation formula for the rotational inertia of the main shaft when simulating the actual vehicle state, the conversion formula for the main shaft speed and vehicle speed, and the calculation formula for the torque to be applied to the main shaft when simulating slope control (in this test bench, the torque is simulated by the ramp resistance loading device during the steep slope start simulation test, and the road slope load or driving resistance is simulated by the bench motor 16 during the road durability test).

[0058] The calculation formula for the rotational inertia of the corresponding spindle when simulating the actual vehicle state is as follows:

[0059] I=Gm r 2

[0060] Where: I is the calculated value of the moment of inertia, unit is kg·m 2 ; G m The maximum design total mass of the vehicle is distributed to the mass of the wheel corresponding to the brake in the sample according to the design value of the braking force distribution ratio, the unit is kg; r is the rolling radius of the wheel, the unit is m;

[0061] The conversion formula between spindle speed and vehicle speed is as follows:

[0062] n=2.65v / r

[0063] Where: n is the spindle speed, the unit is r / min; v is the simulated actual vehicle speed, the unit is km / h;

[0064] The torque required to be applied to the main shaft when simulating ramp control is calculated as follows:

[0065] T s =G m ×sin(arctan(i / 100))×r

[0066] Where: T s The torque required to simulate ramp control is in r / min; i is the ramp gradient in %.

[0067] The above-mentioned accelerated performance test specifically includes the following steps:

[0068] Step 1: Make the test bench motor in a state of free rotation, or keep the rotational inertia simulation running;

[0069] Step 2: Keep the brake in the sample in the released state;

[0070] Step 3: Simulate the maximum opening of the electronic throttle (input the voltage at the maximum opening of the electronic throttle into the controller of the sample through the battery simulator), control the controller output of the sample through the control system, and accelerate the drive motor of the sample to start. Record the time from the given control input signal to the start of the drive motor of the sample to the rotation of the main shaft to reach the simulated real vehicle speed of 100km / h, that is, the 100km acceleration time, and draw an acceleration performance curve with time as the horizontal axis and vehicle speed as the vertical axis, as shown in the attached figure. Figure 2 As shown in the figure, t1 is the acceleration reaction time, t2 is the acceleration time from 0 km / h to v km / h, and when v is equal to 100 km / h, it is defined as the acceleration time per 100 kilometers.

[0071] The above-mentioned medium-steep slope starting simulation test specifically includes the following steps:

[0072] Step 1: Make the gantry motor in a state of free rotation;

[0073] Step 2: Use the control system to control the controller of the sample to simulate pressing the brake pedal or parking condition, so that the spindle is in a locked state. When the controller of the sample is in the parking condition, first control the controller of the sample through the control system to simulate pressing the brake pedal first, and then releasing the parking condition;

[0074] Step 3: Calculate the corresponding torque value according to the following formula based on the ramp to be simulated, and apply it to the main shaft in the reverse direction through the ramp resistance loading device;

[0075] Step 4: Use the control system to simulate releasing the brake pedal. After pausing for a specified time interval, quickly press the accelerator pedal to the set opening, start the drive motor of the sample until the spindle speed is greater than 10r / min, then release the torque applied by the ramp resistance loading device, and record the relationship curve of variables such as the release brake pedal signal, the accelerator pedal control signal, the spindle speed and the torque applied on the ramp resistance loading device over time, so as to obtain the steep slope starting simulation test curve, such as Figure 3 As shown in the figure, A represents the brake holding stage, the steep slope simulation preparation stage, B represents the brake release and no accelerator pedal pressed stage, the uphill assist function check stage, C represents the accelerator pedal pressed, the normal car start simulation stage, and D represents the spindle speed reaching more than 10r / min, the steep slope start simulation end stage.

[0076] By observing the recorded curve, from the time when the brake pedal is released to the time when the accelerator pedal is pressed, and during the starting process when the accelerator pedal is at the set opening and the spindle speed of the test bench is controlled until it reaches 10r / min, whether the spindle speed appears negative can be observed to see whether the reverse slip phenomenon occurs. When a negative number appears, it means that the reverse slip phenomenon occurs.

[0077] When conducting a brake performance test, the prototype is installed to simulate the actual vehicle state, with the prototype's drive motor and controller not in operation or in a disabled state, or the prototype's brake portion is tested separately. Since this part of the test content involves conventional braking performance, the specific test methods can refer to the requirements of standards such as QC / T 239 "Technical Requirements and Bench Test Methods for Commercial Vehicle Service Brakes", GB / T 34422 "Automobile Brake Discs", and GB / T 37336 "Automobile Brake Drums", and will not be repeated here. If the prototype brake is an electromechanical brake, it is only necessary to replace the brake air pressure (hydraulic pressure) input specified in the standard with a brake voltage input.

[0078] The above-mentioned road durability test specifically includes the following steps:

[0079] Step 1: Test cycle conditions are selected based on the standard and the type of vehicle the sample is equipped with, or a multi-level road spectrum is developed based on the user's requirements. Specific test cycle conditions can be selected based on the type of vehicle the sample is equipped with, as per GB / T 38146.2-2019, "China Vehicle Driving Conditions Part 2: Heavy Commercial Vehicles." These conditions primarily include the China City Bus Driving Conditions, China Ordinary Bus Driving Conditions, China Truck (GVW (Gross Vehicle Weight) ≤ 5500kg) Driving Conditions, China Truck (GVW > 5500kg) Driving Conditions, China Dump Truck Driving Conditions, and China Semi-trailer Tractor Train Driving Conditions.

[0080] The China City Bus Driving Cycle (CHTC-B) includes two speed ranges: low speed (Part 1) and high speed (Part 2). The operating cycle market is 1310s in total. The second-by-second data of the operating cycle can be found in Table A.1 in Appendix A of GB / T 38146.2-2019. The operating cycle curve is shown in the figure below. Figure 4 The China Common Passenger Car Driving Cycle (CHTC-C) includes three speed ranges: urban (1), suburban (2) and highway (3). The total driving time is 1800s. The second-by-second data of the driving cycle can be found in Table A.2 of Appendix A of GB / T 38146.2-2019. The driving cycle curve is shown in Figure 5 The China Truck (GVW≤5500kg) driving cycle (CHTC-LT) includes three speed ranges: urban (1 vehicle), suburban (2 vehicles), and highway (3 vehicles). The total driving time is 1652 seconds. The second-by-second data of the driving cycle can be found in Table A.3 of Appendix A of GB / T 38146.2-2019. The driving curve is shown in the figure below. Figure 6 The China Truck (GVW>5500kg) driving cycle (CHTC-HT) includes three speed ranges: urban (1), suburban (2) and high-speed (3). The driving time is 1800s. The second-by-second data of the driving cycle can be found in Table A.4 of Appendix A of GB / T 38146.2-2019. The driving curve is shown in the figure below. Figure 7 The China Dump Truck Driving Condition (CHTC-D) includes two speed ranges: low speed (1 vehicle) and high speed (2 vehicles). The total driving time is 1300s. The second-by-second data of the driving condition can be found in Table A.5 of Appendix A of GB / T 38146.2-2019. The driving condition curve is shown in Figure 8 The China Semi-trailer Tractor Train Operating Condition (CHTC-TT) includes two speed ranges: low speed (1 unit) and high speed (2 units). The operating time is 1800s. The second-by-second data of the operating condition can be found in Table A.6 of Appendix A of GB / T 38146.2-2019. The operating condition curve is shown in the figure below. Figure 9 shown.

[0081] Step 2: Under the required moment of inertia corresponding to the actual vehicle's conditions, the control system controls the frame motor to simulate driving resistance. The voltage input from the battery simulator to the prototype controller simulates the opening of the electronic throttle to control the prototype motor, thereby accelerating, holding, or coasting the vehicle. The pressure input from the brake pressure simulator to the prototype brake simulates the opening of the brake pedal to control the prototype's brakes, thereby decelerating the vehicle. When regenerative braking is involved in the deceleration process, the control strategy of the actual vehicle controller is used to ensure that the vehicle speed corresponding to the spindle speed corresponds to the second-by-second data of the test cycle condition, and the test cycle continues until the specified cycle is completed.

[0082] Step 2: After the cycle is complete, inspect the sample components for abnormalities such as wear, cracking, deformation, and failure, as well as performance and functional degradation in acceleration, braking, and energy recovery. If necessary, the sample's power consumption per 100 kilometers under a specific cycle condition may also be measured.

[0083] The above regenerative braking simulation test specifically includes the following steps:

[0084] Step 1: Turn on the braking energy recovery function and keep the battery simulator in energy feedback mode.

[0085] Step 2: Select the initial braking speed according to the regulations (50km / h and 80km / h for N1 vehicles, 30km / h and 60km / h for other types of vehicles), and take no less than five points for testing within the specified braking pressure range, and the intervals between the test pads are equal. Conduct a braking test for each braking pressure corresponding to each initial braking speed, and record the measured battery simulator voltage and feedback current during each braking test, as well as the initial braking speed, initial braking temperature, maximum braking temperature, braking time, braking pressure and output braking torque of each braking test. Calculate the recovered braking energy using the recovered braking energy calculation formula.

[0086]

[0087] Where: E1 is the energy recovered by the regenerative braking system during a single braking process and ultimately fed back to the battery simulator, in Wh; I is the current fed back to the battery simulator during a single braking process, in A; U is the voltage across the battery simulator during a single braking process, in V; t1 is the start time of the effective braking time period, in seconds; t2 is the end time of the effective braking time period, in seconds.

[0088] Depending on actual needs, the operating condition method can also be used to conduct the brake energy recovery efficiency test. The test cycle conditions can be selected based on the cycle conditions in the road durability test, and the test method can refer to QC / T 1089-2017 standard B.4.

Claims

1. A method for conducting a real vehicle simulation test of a commercial vehicle brake pulley side electric drive assembly using a test bench, characterized in that: The test bench comprises an environmental simulation box (3) for simulating temperature, humidity and wind speed in an actual environment, and the environmental simulation box (3) is covered at the left end of the test bench (6), and is characterized in that: the test bench (6) is located in the environmental simulation box (3) and is provided with a mounting table (4) for mounting a sample (5), an intermediate support seat (8) is provided on the test bench (6), and the intermediate support seat (8) is located outside the environmental simulation box (3), a first transmission shaft (7) is provided on the left side of the intermediate support seat (8), the first transmission shaft (7) extends into the environmental simulation box (3) and is connected to the output shaft of the sample (5), and the right side of the intermediate support seat (8) is provided with a first transmission shaft (7). A second transmission shaft (11) is provided, a torque sensor (9) is provided between the first transmission shaft (7) and the second transmission shaft (11), a flywheel shaft is provided on the right side of the second transmission shaft (11), the flywheel shaft is mounted on a flywheel frame (12) of the test bench (6), at least one flywheel disc (13) is sleeved on the flywheel shaft, a third transmission shaft (15) is provided on the right side of the flywheel shaft, the right end of the third transmission shaft (15) is connected to a bench motor (16) fixed to the right end of the test bench (6), and the combination of the first transmission shaft (7), the second transmission shaft (11), the flywheel shaft and the third transmission shaft (15) becomes a main shaft; The invention also includes a control system (17), a brake pressure simulator (10) connected to the brake of the sample (5), a battery simulator (1) electrically connected to the regenerative braking system and controller of the sample (5), a liquid cooling circulation system (2) for simulating the temperature of the cooling medium in the sample, and a slope resistance loading device (14) for simulating steep slope starting. The brake pressure simulator (10) simulates the pressure input to the brake of the sample when the brake pedal is depressed by the input brake pressure. The battery simulator (1) simulates the battery power supply of the car by the voltage input to the controller of the sample. The battery simulator (1) is also used to simulate the sample recovering the braking energy under the regenerative braking condition. The brake pressure simulator (10), the torque sensor (9), and the battery simulator (1) are all electrically connected to the control system (17). The liquid cooling circulation system (2) is connected to the cooling system of the sample (5) through a pipeline. The slope resistance loading device (14) includes a slope loading motor. The output end of the slope loading motor is provided with a speed reducing torque increaser and a torque limiting component. A transmission component is provided between the torque limiting component and the flywheel shaft. The sample (5) is mounted on the mounting table (4) to simulate the actual vehicle state, and the output shaft of the sample (5) is connected to the first transmission shaft (7), and the battery simulator (1), the liquid cooling circulation system (2), the brake pressure simulator (10), and the control system (17) are connected. The actual vehicle state is achieved by adjusting the number of flywheel discs on the flywheel shaft that can rotate with it, and simulating the rotational inertia through the control system (17) and the bench motor (16), so that the main shaft has the same load as when the sample is mounted on the actual vehicle and starts; then the acceleration performance test of the sample, or the steep slope starting simulation test, or the braking performance test, or the road durability test, or the regenerative braking simulation test is carried out. The formulas required to be used during the test include the calculation formula for the rotational inertia of the main shaft corresponding to the actual vehicle state, the conversion formula for the main shaft speed and the vehicle speed, and the calculation formula for the torque to be applied to the main shaft when simulating slope control; The calculation formula for the rotational inertia of the corresponding spindle when simulating the actual vehicle state is as follows: I=G m r 2 Where: I is the calculated value of the moment of inertia, unit is kg·m 2 ; G m The maximum design total mass of the vehicle is distributed to the mass of the wheel corresponding to the brake in the sample according to the design value of the braking force distribution ratio, the unit is kg; r is the rolling radius of the wheel, the unit is m; The conversion formula between spindle speed and vehicle speed is as follows: n=2.65v / r Where: n is the spindle speed, the unit is r / min; v is the simulated actual vehicle speed, the unit is km / h; The torque required to be applied to the main shaft when simulating ramp control is calculated as follows: T s =G m ×sin(arctan(i / 100))×r Where: T s The torque required to simulate ramp control is in r / min; i is the ramp gradient in %.

2. The method for conducting a real vehicle simulation test of a commercial vehicle brake pulley side electric drive assembly using a test bench according to claim 1 is characterized in that: The accelerated performance test comprises the following steps: S1: Let the test bench motor be in a free-rotating state, or keep the rotational inertia simulation running; S2: Keep the brake in the sample in the released state; S3: Simulate the maximum opening of the electronic throttle. Control the controller output of the sample through the control system to accelerate the drive motor of the sample. Record the time from the given control input signal to the start of the drive motor of the sample to the rotation of the main shaft to reach the simulated real vehicle speed of 100 km / h. Draw an acceleration performance curve with time as the horizontal axis and vehicle speed as the vertical axis.

3. The method for conducting a real vehicle simulation test of a commercial vehicle brake pulley electric drive assembly using a test bench according to claim 1, characterized in that: The steep slope starting simulation test comprises the following steps: S1: Make the gantry motor in a free-rotating state; S2: The control system controls the controller of the prototype to simulate pressing the brake pedal or parking conditions, so that the spindle is locked. When the prototype controller is in the parking condition, the control system controls the prototype controller to simulate pressing the brake pedal first and then releasing the parking condition. S3: Calculate the corresponding torque value according to the formula based on the ramp to be simulated, and apply it to the main shaft in the reverse direction through the ramp resistance loading device; S4: Use the control system to simulate releasing the brake pedal. After pausing for a specified time interval, quickly press the accelerator pedal to the set opening to start the drive motor of the sample until the spindle speed is greater than 10r / min. Then release the torque applied by the ramp resistance loading device. Record the relationship curve between the brake pedal release signal, the accelerator pedal press control signal, the spindle speed and the torque applied on the ramp resistance loading device over time, so as to obtain the steep slope starting simulation test curve.

4. The method for conducting a real vehicle simulation test of a commercial vehicle brake pulley electric drive assembly using a test bench according to claim 1, characterized in that: When conducting a braking performance test, the sample is installed to simulate the actual vehicle state, the drive motor and controller of the sample are not involved in the work or are in a non-enabled state, or the brake part of the sample is tested separately, and the test steps are carried out in accordance with the standard requirements.

5. The method for conducting a real vehicle simulation test of a commercial vehicle brake pulley electric drive assembly using a test bench according to claim 1, characterized in that: The road durability test comprises the following steps: S1: The test cycle conditions are selected according to the standard based on the type of vehicle the sample is equipped with, or a multi-level road spectrum is formulated according to the requirements of the user; S2: Under the requirements of the moment of inertia corresponding to the simulated actual vehicle state, the control system controls the frame motor to simulate driving resistance, and controls the sample motor by changing the opening of the electronic throttle to simulate the acceleration, holding or coasting of the vehicle. The brake of the sample is controlled by changing the opening of the brake pedal to simulate the deceleration of the vehicle. When regenerative braking control is involved in the deceleration process, the control strategy of the actual vehicle controller is used to make the vehicle speed corresponding to the spindle speed correspond to the second-by-second data of the test cycle condition, and continue to run until the end of the specified cycle; S3: After the cycle is completed, inspect the abnormal conditions of each component of the sample as required, as well as the performance and function degradation after endurance.

6. The method for conducting a real vehicle simulation test of a commercial vehicle brake pulley side electric drive assembly using a test bench according to claim 1, characterized in that: The regenerative braking simulation test includes the following steps: S1: Turn on the braking energy recovery function; S2: Select the initial braking speed as specified, and conduct tests at no less than five points within the specified braking pressure range, with equal intervals between each test point. Conduct a braking test for each braking pressure corresponding to each initial braking speed, and record the measured battery simulator voltage and feedback current during each braking test, as well as the initial braking speed, initial braking temperature, maximum braking temperature, braking time, braking pressure, and output braking torque of each braking test. Calculate the recovered braking energy using the recovered braking energy calculation formula. Where: E1 is the energy recovered by the regenerative braking system during a single braking process and ultimately fed back to the battery simulator, in Wh; I is the current fed back to the battery simulator during a single braking process, in A; U is the voltage across the battery simulator during a single braking process, in V; t1 is the start time of the effective braking time period, in seconds; t2 is the end time of the effective braking time period, in seconds.

7. The method for conducting a real vehicle simulation test of a commercial vehicle brake pulley electric drive assembly using a test bench according to claim 1, characterized in that: Each flywheel disc (13) can be fixed on the flywheel frame (12) through a corresponding detachable fixing structure, wherein the detachable fixing structure includes two fixing brackets located outside the corresponding flywheel disc (13) and fixed on the flywheel frame (12), and the flywheel shaft is provided with a protrusion that can be clamped with the corresponding flywheel disc; when the flywheel disc (13) rotates together with the flywheel shaft, the flywheel disc (13) is sleeved on the protrusion and connected to the flywheel shaft by bolts, and the fixing bracket and the flywheel disc (13) are not connected; when the flywheel disc (13) does not rotate together with the flywheel shaft, the flywheel disc (13) is sleeved on the flywheel shaft except the protrusion and the bolt connection between the flywheel shaft and the flywheel shaft is disconnected, and the fixing bracket and the flywheel disc (13) are connected by bolts.

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